| 摘要 |
PURPOSE: To improve heat-insulation characteristics by simultaneously biaxially orienting a multilayer sheet having an outside sheet layer made of a polypropylene and an inside sheet layer made of an ethylene-vinyl alcohol copolymer. CONSTITUTION: In the case that an ethylene-vinyl alcohol copolymer is remarkably ethylenic, sufficiently biaxially orientation of the sheet can be performed. Heat-insulative characteristics of the sheet oriented in the other side are clearly improved by the slight ethylenic. In the multilayer having the outside sheet layer made of the polypropylene, lateral and longitudinal draw ratios are particularly advantageous in the case of about (7-8) to 1. An optimul value of the characteristics is performed by the high ratio of this type in both the directions. In this case, an areal draw ratio within 1:49 to 1:64 is particularly advantageous. |
